Mutation of albedo and growth response produces oscillations in a spatial Daisyworld

We present an extension of a 2-dimensional cellular automata (CA) Daisyworld to include mutation of optimum growth temperature as well as mutation of albedo. It is well established for only the latter case that such models exhibit homeostasis of the environment temperature in this case. In our model the organisms (daisies) can adapt to prevailing environmental conditions or evolve to alter their environment. This setup therefore allows us to examine whether or not the former inhibits or even destroys the homeostatic effect. We find the system to be capable of regulation on average but that it oscillates with a period of hundreds of daisy generations. The ability of the daisies to alter their optimal growing temperature leads initially to a planet which is less able to sustain itself, but the planet becomes steadily more stable (on average) for greater rates of genetic drift in this characteristic. Weaker and less regular oscillations have already been predicted in Daisyworlds before but in this model they become stronger and more regular as the mutation rate of the optimum growth temperature is increased. This demonstrates that long period oscillations can be generated internally by even highly simplified earth models. Here a new timescale is induced by including evolutionary dynamics, a effect not normally included in such models.